Approximately 7,700 years ago in Klamath County, Oregon, Mount Mazama exploded and collapsed, forming a 2,148-foot-deep caldera that eventually filled with fresh water to a depth of 1,949 feet. Known to the local Klamath people as Giiwas and to settlers first as Deep Blue Lake, then Blue Lake, Lake Majesty, and finally, Crater Lake, it is the deepest lake in the United States and the ninth deepest lake in the world.
The lake is simply too large to capture except by iPhone panorama, as above, but here are some other photographs, and it really is this blue. There are two islands in the lake: Wizard Island, and the Phantom Ship rock pillar.
While the Phantom Ship looks small in the photograph, it is 170 feet high: roughly the same height as a 15-story building.
Next: on to Salt Lake.